bayles



L. C. BAYLES.

FLUID OPERATED PERCUSSWE TDUL. APPLICAHON FILED Auehao, 1919.

Patented June 15, 1920.

2 SHEETS-SHEET I.

IN VEN TOR.

A TTORNEYS.

L. (J. BAYLES.

UND UFLRATED PERCUSSIVE TOOL. Am-Limnor'v men M1930, 1919.

l ,3 3 1 Patented June 15, 1920.

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9 M v INVENTOR- 7a 2Q AW .4 TTORNEYS.

UNITED STAT-ES PATENT OFFICE.

LEWIS O. BAYLEB, OF EASTOH, PENNSYLVANIA, ASSIGNOR T0 INGEBSOLL-BAHD .GOII'AJTY, OI JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

To all whom it may concern:

Be it known that I LEWIS O. BAYLES, a citizen of the Unite States residing at Easton, in the county ofNorthampton and State of 'lennsylvama, have invented a certain new and useful Improvement in Flu1d- Operated Pcrcussive Tools, of which the following is a specification.

This invention relates to a fluid operated percussive tool, and in particular to a fluid operated tool having a piston of two diameters and adapted to strike a drill steel or other tool at the end of its forward stroke.

The objects of the present invention are to improve the operation of percussive tools of the above type, to make their operation steadiencasior to start and to prevent dead centering.

A further object'of the invention is to provide means to continue the admission of fluid to ohe end of the cylinder after the main admission port is closed, to increase the mean effective pressure in that end, thus increasing; the force to return the piston to its initial position.

With these and other objects in view my invention consists in the features of construction and operation set forth in the following specification.

Referring to the drawings attached hereto and forming a part of this s ecifieation.

Figure 1 shows a longitu inal view in sec tion of a percussive tool provided with the present invention.

. der and piston of a drill triads in accor once igs. 2 3 and 4c are, respectively, sections taken on lines 2-2, 3-3 and 4 -4 of F ig. 1.

Fig. 5 shows diagramnmtically the 0 1mwith the present invention, the piston being shown at the beginning of it's forward stroke.

Figs. 6, 7 and 8 are diagrammatic views I similar to Fig. 5, with the piston in different positions of its stroke. 1

In percussive tools und es ecially in percussive drills used-in rock dri ling, it is usual to provide means to rotate the drill steel simultaneously with the reciprocation of the piston; and in many of the drills as now used the rotation arts are so applied that during the striking ilow of the piston, the piston is free and simply has to turn a very light and easily rotated part of the rotating mechanism,'bnt on its reverse or upstroke the piston is rotated a part of a revolution and the Specification of Letters Patent.

Application filed August 30, 1919. Serial No. 820,909.

Patented J une 15, 1920.

front chuck and drill steel also similarly rotated. Operating the rotation in this manner does not lessen the striking ower or blow of the piston materially but is open to a possible objection that in the event of the upstroke of the piston not being powerful enough, the rotation will not operate. a The present invention relates particularly to a construction admitting of a very powerful upstroke which can be utilized to advantage in increasing the power of the rotation. The cfl'ect of a more powerful upstroke may also be noticeable in increasing the number of blows per minute by reason of the fact that the more powerful upward stroke sickens the speed of the upward stroke. he downward or o ver blow of the piston is in no way effects by the present invention. Referring now more particularly to the drawings, 1 refeis to the cylinder, 2 a piston operated therein, having a head 3 and a shank portion 4 at its rear end. The forward end of the piston is fluted as shown at 5 formwithin a bore 8 of smaller diameter. The

piston shank 4 1s suitably bored and rifled flutes 2'3 engaging corresponding grooves in the rifled portion of the shank 4. The rear end of the rifled member 25 is provided with a head 27 in which is located a spring pressed pawl 28. 'In alinement with this head 27 is a notched member 29 set into a back head 30 so that movement of the piston on itsfforward stroke rotatesthe rifled member 25 and permits the awlto slide over one or more notches in the member 29 but on its rear movement is forced to rotate itself and thereby rotate the chuck 6 and drill steelG, the pawl. meanwhile engagin one of the notches .and reventing retrogra e movement of the Pill member 25.

Motive fluid. usually compressed air or, in

some instances steam, enters orifice 9 from to take the rifled memlfir 25 having spiral 5 a passage is opened by neck 12 of the piston to admit motive fluid to the rear end'of the cylinder bore 7. A conduit 13 has an orifice 14 as shown about midway 'of the bore 8 of the cylinder at its rear end, the other end being at the forward end of bore 7 so that when the piston is in the forward end of the cylinder, a passage is opened for the supply of motive fluid to the front end of the cylinder bore 7. All of these parts, including the conduit 13, are similar in every respect to my construction shown and described in Patent No. 1. 368,081 granted J due 4, 1918. Preferably the present construction may be provided with a supplemental exhaust mechanism comprising avalve 16 openin and closing conduits 17 and 18 at the en 5 of the cylinder bore 7. The corn lnon central exhaust port 19 is also applied as is usual in this form of tool. This method of exhausting the fluid from the cylinder is similar in every way to that described in Patent No. 1,278,237 granted Sept. 10, 1918, and will therefore require no further description.

It will be seen from the above description that no fluid is admitted to the forward end of the cylinder 7 until the rear end of shank 4 passes or overruns the orifice 14 of the conduit 13 and then as soon as this orifice 14 is closed on the reverse movement of the iston 2 no additional fluid will be supplied l t is therefore an object of the present in vention to provide means to continue the supply of fluid to the forward end of cylinder bore 7 until the -piston 2 has made a larger portion of its reverse stroke, thus increasin the pressure withT-i the forward end of here 7 to forpe the piston renrwardly and prevent it from slowing up or stopping. This means comprises an extra or auxiliary conduit 20, its rear orifice openinn into bore 8 of the cylinder being at point as shown at 21 which 18 about three-fourths the total len h of the bore 8 from its forward end. his conduit 20 is shown intercepting a convenient point in the. conduit 13. In operation of the piston which will be clearly evident from inspection of Fig. 5 et seq. as soon as the piston 52 on its forward stroke indicated by the arrow in Fig. 5, passes the orifice 21, a slight amount of fluid is allowed to pass into conduit 13. The amount passino. however, is not sullicient to materially increase the amount of fluid sup lied during the down stroke of the piston, Jspeciall is this. so because the forward stroke 0 the piston being free from any drug on the rotation parts is very rapid and the instant of time during which the conduit 20 is open before the main conduit 13 is open is very trifling; During this forward stroke the slight amount of fluid su plied through conduit 2-0 passes from the orward end of bore 7 -through conduit 17 and past valve 16 which is in the position shown in Figs. 1 and 5. During the rear stroke, however, which as above indicated, is slower than the forward stroke, due to the dra I and pull of the rotation parts, the time luring which the conduit 20 remains open and supplying fluid to the forward end after the main port of the conduit 13 is closed is very material and effectively increases the power and speed of the rear stroke of the piston. The harder the rotation pulls or drags on the piston the'slower will be the up or rear stroke of the piston and thus a longer time will elapse for fluid to use through conduit 20 into the forward ent of bore 7.. In practice it has been found that the power of the rear stroke of the piston has been so greatly increased by the inclusion of conduit 20 that the rotation parts will h are an proximately four times the power compared with thcpower when operating without the auxiliary conduit 20.

Referring again to Figs .3 to H the proportions of the cylinder bores and the relative position of the ports and conduits for the supply and exhaust of motive fluid will be clear. Starting with the piston at the beginning of its stroke as shown in Fig. 5, motive fluid is supplied at constant pres sure to the rear face of the shank 4 throughout the entire stroke of .the piston 2, and also for a portion of the forward stroke is supplied to the rear of bore 7 of the cylin der. The port '21 o ens when the piston has made between one fth and one fourth of its stroke and approximately simultaneously therewith the port 11 closes thus cutting off the sup ly of fluid to the rear of bore 7 of the c'y inder (see Fig. 8).

As above indicated the amount of fluid, supplied, to conduit 13 and to the forward end ofo'pore 7 during the ra id forward stroke the piston is relative y small. and serves onl to increase slightly the air consumption ut does not cushion the blow of the dpiston 2 upon the drill steel 6" as fiui may pass out throu h conduit 17. During tie rear stroke of t e piston, however, which as above stated is much slower than the forward stroke due to the drag of the rotation parts, the port 21 is open for a longer period of time so that a much lar er amount of fluid passes through conthis duit 20 and into the forward end of the bore 7. This has the effect of continuin the sup ly of fluid to the forward end of bore 7 a or the main supply has been cut off by the shank 4 overrunnlng port 14. As shown in {F i 8, this port 21 remains open approxL ithout the conduit 20, if the drag of the Hi the piston at: e pressure areas, and

rotation on the piston 21 stops it after the port 14 is closed the pressure of the fluid in the forward end of bore 7 falls materially due to leakage and the piston remains at rest. With the conduit 20, if the piston should come momentaril to rest the pressure in the forward on of bore 7 would graduall build up, thus forcing the piston rearwar ly until the central exhaust port 19 opens and the supply port 11 opens when would strike another blow. Furthermore without conduit the piston may dead center or stop at an position on its back stroke between the closing of port 1-1 and the opening of port 19 while with conduit 20 the only sition at which the piston can dead center is on a line where the conduit 20 is just closing and port 19 is just opening, this conditionvbeing almost impossible to produce.

The above description covers but one exemplification of the invention and it is to be understood that it is illustrative only and not limiting or restrictive of the invention.

Having thus described my invention, what I claim 1s:

1. In a fluid operated percussive tool, a cylinder having a bore of two diameters, a pistontherein having portions fitting hoth diameters of said cylinder, said piston havin a constant pressure area and two var-i means comprising a small port near the rear end of the smaller diametered portion of the cylinder and a larger port about midway of the smaller bore of the cylinder and overrun by the con stant pressure area of the piston to admit pressure fluid to force the piston in one direction.

2. In a fluid operated percussive tool, a cylinder having a bore of two diameters, a piston therein having portions fitting both bores of'the cylinder, said iston having two pressure areas to drive it orwardly and one to return it, larger and smaller ports intercepting a constant pressure chamber of the cylinder and overrun by one end of said piston to convey fluid pressure to the forward end of the c linder to return the piston, the smaller 0 said ports being located rearward of the larger ort and remaining open approximately until the exhaust portopens, to maintain the pressure at the front of the piston to prevent the piston slowing up or stopping.

3. In a fluid operated percussive tool, a cylinder having a bore of two diameters, a piston therein havin portions fitting both diameters of said cylinder, said piston having a constant pressure area and two variable pressure areas, and means comprising a main port and a small leak ort spaced apart longitudinally of the smaller bore of the cylinder and overrun by the constant pressure area of the piston to admit pressure to force the piston in one direction, the small leak port being the port first opened and last closed by the piston, whereb pressure is built up at the front end of t e piston in case the piston slows up or stops.

In testimony whereof I have hereunto set my hand.

LEWIS o. BAYLES. 

